1. Field of the Invention
The present invention relates to a local drug delivery for periodontal disease treatment and, in detail, it relates to a local drug delivery film for periodontal treatment containing a periodontal therapeutic agent for an active component and a mixture of two kinds of polycaprolactone having different molecular weights, which has excellent sustained releasing properties with effective concentration for periodontal treatment, can be prepared easily by melt casting and has a excellent stability in a human gingival fibroblast.
2. Description of the Prior Art
Recently, concerns about the development of new kinds of drug have been emphasized but the cost is prohibitive. Alternatively, many researches relating to the development of various kinds of local drug delivery to increase the effect of a prescription of a conventional active component show a tendency to increase. Particularly, there were many suggestions in the field of treatment for diabetes, hypertension, cancer and periodontal disease.
Since tetracycline-filled cellulose acetate hollow fiber was proposed at first by Goodson et al. ("Periodontal therapy by local delivery of tetracycline" J. Clin. Periodontal., 6: 83, 1979), many kinds of release control systems were studied using dialysis tube, polyethylene, polypropylene, ethylene vinyl acetate, polycaprolactone, collagen, acrylic strip, etc. Particularly, in the case of the cellulose acetate as release control material, release controlled drug delivery was studied in the form of hollow fiber or film.
But, concerning the results of these studies, in the case of tetracycline-filled hollow fiber prepared by Goodson et al., 95% of tetracycline was released within 2 hours, the half life of release (t.sub.1/2rel) was about 0.5 hour and the concentration of tetracycline in gingival fibroblast was 15 .mu.g/ml after 24 hours.
This non-sustained release was also shown in conventional local drug delivery using dialysis tube, polyethylene, polypropylene, polyurethane, polycaprolactone and cellulose acetate, and most drug contained in such preparations was released within 24 hours.
In case of ethylene vinyl acetate fiber, sustained release pattern was shown for 9 days, but initial release concentration was 650 .mu.g/ml and the half life of release was 13 hours. That is, even if the effect of the drug itself came out, there was a tendency that the durability of the effect of drug was on the decrease.
Also, jelly-type delivery system containing 2% of minocycline was studied in Japan, in which the concentration of minocycline in gingival fluid decreased rapidly till 7 hours after prescription and was 3.4 .mu.g/ml after 3 days and 0.1 .mu.g/ml after 7 days. That is, there was the effect of drug itself, but there was a tendency that durability of the effect of drug was on the decrease.
To solve these problems, the present inventor developed a local drug delivery film which increased the durability of the effect of drug by mixing of the tetracycline as an active component and biodegradable polycaprolactone as a release control component, and filed with Korean patent application No. 1990-4398. This film is prepared by solution casting including dissolving a polymer in a solvent, adding an active component or its suspension into the polymer solution, mixing together homogeneously and volatilizing the solvent. Accordingly, there are several problems, that is, the potential existence of toxic solvent residue and non-uniform dispersion of active components in the film due to irregular volatilization of solvent giving rise to the unsteady pattern of drug release. Therefore there is room for improvement.